There are comments that you should not adjust the gap sizes of the plugs and use them the way they come out of the box. Hmmm .. I have a 1999 Grand Prix GTP with the 3.8L V6 supercharged engine. My GM owners manual states a gap of .060 for all the replacement plugs listed not only for my engine but for all Grand Prix engine sizes of that year 3.1 / 3.8 / 3.8SC Check your GM owners manual .. it will state there in the section of different replacement parts, what spark plugs to use and the gap size
Chat with our AI personalities